Superheater



N. T. McKEE.

SUPERHEATER.

APPLICATION FILED FEB. 25, 1920.

1,395,131, Patented Oct. 25, 1921.

3 SHEETSSHEET I.

IIIII/II/IIII/I/villi/117111171117 1/11/10:

NEAL Z M; A155. gvyvewto'o N. T. McKEE.

SUPERHEATER.

APPLICATIDN FILED FEB. 25. 1920.

Patented Oct. 2, 1921.

3 SHEETS-SHEET Z- N. T. MCKEE.

SUPERHEATER.

APPLICATION FILED FEB. 25. 1920.

1,395,131 I Patented Oct. 25, 1921.

3 SHEETSSHEET 3.

4454/. 77 Ma /f vwzmtoz UNITED STATES PATENT OFFICE.

NEAL TRIMBLE MOKEE, OF YONKERS, NEW YORK, ASSIGN'OR TO THE SUPERHEA T'EB COMPANY, OF NEW YORK, N. Y A CORPORATION OF DEL'AWARE.

SUPERHEATER.

' To all whom it may concern:

Be it known that I, NEAL TRIMBLE Mo- KEE, a citizgn oithe United States, and resident of Yonkers, in the county of Westchester and State of New York, have invented certain new and useful Improvements in Superheaters, of which the following is a specification.

This invention relates to superheaters and particularly to superheaters used in connection with locomotives, although its use is not limited to that particular field. I

In structures of this class it is a fact that due to the practical limitations under which the designer has to labor the degree of superheat is not constant under varying speeds, but increases as the speed and steam consumption go up. The result is that the superheater of the locomotive being designed for average conditions of load to be met by it, the locomotive Works under conditions tending to cut down the efiiciency at low loads.

The present invention has for its purpose the provision of mechanism to obviate this difiiculty and to make it possible to obtain a more nearly uniform degree of superheat at all loads.

The invention is illustrated in the accompanying three sheets of drawings, in which:

Figure 1 shows a longitudinal central-sectional view of the fore part of a locomotive with my invention applied, only such por tions of the locomotive being shown as are required to make the relation and action of my device clear;

Fig. 2 is a sectional view on line 2-2 of Fig. 1; portionsbf the header being shown in section on line 2f?- Fig. 3 is a top view of a portion of the mechanism employed;

Fig. 4 is a sectional detail of one of the valves;

Fig. 5 is a view 'similar to- Fig. 1 of a modification; 1

Fig. 6 shows another modification, the gem-being a sectional one similar to that of Fig. 7 is a sectional view on line 7-7 of Fig. 6;

Specification of Letters Patent.

Application filed February 25, 1920. Serial No. 361,306.

Figs. 8, 9 and 10 illustrate a further modification; Fig. 8 being a fragmentary section on line 8-8 of Fig. 10; Fig. 9 being an enlarged central longitudinal section of a valve of this modification; Fig. 10 being a top sectional view of Fig. 8 on line l0-10;

and Fig. 11 is'a sectional detail view of the 1 governor used in connection with this invention.

The general arrangement and function of the boiler parts are not modified in applying my invention. Thus in Figs. 1 and 2 we have the usual boiler shell 1, the smokebox shell 2, the flue sheet 3 separating the boiler space from the smokebox, the iiues 4 to conduct the products of combustion from the firebox (not shown) to the smokebox, and the stack 5 by which these products leave the smokebox. 6 is the usual exhaust pipe located under the stack extension 7 to create the required draft. Extending into the flues 4 are the superheater elements 8. These elements are of the ordinary wellknown construction, their two ends being connected to the header 9. A drypipe 10 delivers steam to the header and a pair of steam pipes 1111 (only one visible), con nected to the outlets 12-12, carries the superheated steam from the header to the steam chests. These parts are, with'one exception, not, modified in my arrangement. The header which is modified also has, as is the case in the form of header almost universally used at present, a pair of interleaved sets of chambers 13 and 14, those numbered 13 all communicating with a cross-channel 15, and those numbered 14 all connected to the cross-channel 16. Each superheater element has one and connected to a chamber 13 and the other to a chamber 14. The modification alluded to above consists partly in that channel 16 has a partition 16 in it, separating it into two parts, the purpose of which will appear presently. In the ordinary form of header steam is delivered directly from the dry pipe 10 to the channel 15 and passes directly from channel 16 to the outlets 12.. in my device,

up to a. predetermined speed, permit steam to pass by a short and direct path from the dry pipe to channel 15 and by a short and direct path from channel 16 to outlets 12; but mechanism is provided to prevent such direct passage at times when the locomotive is moving below such speed.

This mechanism comprises two piston valves numbered respectively 17 and 18. The former of these controls the two ports 19 and 20, and, as will be clear from Fig. 1, can put either into communication with dry pipe 10 throu h passages 21 and 22 and connection 23. Fort 20 opens into passage 15. Port 19 leads to the assage 24 which extends across the top of the header (see Fig. 2) and leads to the port 25. This port and ort 26 are controlled by valve 18. \Vhen both ports are spanned by the valve, as in Fig. 1, channel 24 is in communication with the right portion of channel 16 (the lower, asshown in Fig. 2). When valve 18 is in its upper position, the communication spoken of is interrupted; and communication is then established between the right portion of channel 16 and the cross channel 27 through port 26: The two valves 17 and 18 are to be moved into upper or lower positions in unison. While this may evidently be accomplished manually by simple mechanism, I prefer to make the entire operation automatic. To this end I carry the stems 28 and 29 from valves 17 and 18 through stufling boxes and connect them respectively to the bell crank levers 30 and 31, links 32 and 33 being interposed. The levers are pivoted at the fixed points 34 and 35, their other arms being connected by pins to the rod 36. This rod 36 is connected by link 37- to the piston rod 38 of the piston 39, reciprocable in the cylinder 40. The end of the cylinder remote from the rod 36 and the attached mechanism is supplied with steam by the plpe 41, while opposing the pressure exerted on the piston 39 by this steam is the spring 42. Steam is supplied to pipe 41 from the saturated side of the superheater header through pipe 43, the delivery from 43 to 41 being controlled by the governor 44. This governor is of any usual or preferred construction and establishes and interrupts communication from pipe 43 to pipe 41 in response to the pressure difference between the header and the steam pipe 11, pipe 45 supplying steam from the, latter source. When the pressure difference is below a predetermined point the valve 44, controlling the communication between pipes 45 and 41, re-

mains closed; but when it exceeds this point,-

- which is-carried by the differential piston 102. The upper and smaller surface of this meager piston is subject to pressure from pipe 45, and the lower and larger to pressure from pipe 43. Spring 103 acts on the piston in the same direction as pressure on the smaller area, and is so adjusted by means of nut 104 that the valve opens at the desired pressure difference.

The action of my arrangement may now be described.

Suppose the throttle is open and the locomotive moving slowly. At such times the drop in pressure between the saturated side of the header and the superheated side (or steam pipe 11) is very small and the governor 44 will therefore act to keep the communicationbetween pipes 43 and 41 closed. Spring 42 will keep piston 39 in the position indicated in the drawing and valves 17 and 18 Will occupy their lower positions as in the drawing. Steam from dry pipe 10 cannot pass port 20 but goes by way of passage 21 and port 19 to the channel 24. This channel delivers it to the right portion (lower portion, Fig. 2) of channel 16 and so to the three chambers numbered 14 which open into the right portion. It should be noted that the partition 16 prevents the steam at this stage from reaching the left portion of passage 16. From the three chambers 14 mentioned the steam passes into those superheater elements 8 which have their first ends connected to them. They return it in a superheated state to those chambers 13 to which they are connected. These chambers are, for the sake of clearness, given reference characters AAA in the drawing, Fig. 2. From these chambersthe steam passes by way of channel 15 to the remaining chambers 13, marked B-B in Fig. 2. Thence it leaves by way of the superheater elements 8 communicating with them, and thus reaches the remaining chamhers 14, those, a. e., to the left of (or above, Fig. 2) partition 16*. They in turn deliver it to the left portion ofchannel 16, whence it reaches the transverse channel 27 and so the two outlets 12-42, and steam pipes 1111.

It will be noted that the effect of the arrangement under the conditions mentioned is to make the steam circulate first through one portion of the superheater elements and thereafter through the other portion, instead of through all of them simultaneously or in parallel. The rate at which the steam is flowing within the elements is as a consequence approximately doubled compared with itsrate if the flow were in parallel. This more rapid flow results in a much more rapid heat transfer, as will be well under stood by those conversant with the principles of heat transfer, and the steam will therefore be superheated to a higher degree than would be the case otherwise. In other words, the drop in superheat at low loads is entirely alinement with valves .drained from the spaces above opposing spring '61.

or in a large measure obviated. ()n the other hand the resulting restricted cross-sectional area. for the steam flow is not objectionable at such times, because the steam consumption is low.

After the locomotive has picked up speed, a pressure drop between the saturated side of the header and the steam sufi'icient to operate the properly adjusted governor 44 so that it will admit steam to cylinder 40. The pressure of this steam moves the piston 39 to the right, thereby raising valves 17 and 18. his movement closes port 19, 0 ens port 20 and establishes communication etween passage 16 and the right portion of passage 27 through port 26. Steam from the dry pipe 10 will now reach cross-channel .15 directly through passage 22, flow at once to all the chambers 13, both those marked A-AA and those marked B-B, pass through all of the superheater elements in parallel, and reach chambers 14 and both portions of channel 16. From the right ortion it will reach transverse channel 27 y way of port 26; from the left portion it-will flow directly into said channel. From there on the steam reaches the valve chests by way of outlets l2-12 and steam pipes 1111 as before.

With valves 17 and 18 in the position just described the steam flow is'therefore entirely similar to the flow as it occurs with the ordinary header. The same degree of superheat can therefore be attained.

In the variation of Fig. 5 the mechanism within the boiler and smokebox shells will be noted to be the same as that just described. The means for actuating the two valve stems 28 and 29 however is given a diflerent form. Instead of the two being moved by'a single piston, each is moved by its own. These pistons, numbered 50 and 51, reciprocate in the cylinders 52 and 53, in

28 and 29 respectively. The steam to actuate these pistons is supplied by pipe 54 connected to any convenient source of live steam, and is controlled by the piston valve 55. With valve 55 in the upper position, as shown in the figure, steam from 54 can evidently reach the upper portions of cylinders 52 and 53 by means of connecting pipes 56 and 56"; While with it in lower position, the steam would reach the lower ends of the cylinders through pipes 57 and 57 Leakage is and below piston valve 55 by pipes 58.

he position of valve 55 is changed from upper to lower by means of piston 59, connected to the valve by the rod 60, and by the With steam pressure acting on the upper side of59 the force of the spring 61 is overcome and the piston 59 and valve 55 are forced to their lower positions; but with the pressure above 59 out 01f,

pipe develops,

and the other through the spring 61' forces them to their upper position.

Pressure to the upper side of piston 59 is supplied by pipe 43 and is controlled by the governor 44, exactly as the steam supply to cylinder 40 is controlled in the form of F ig. 1. The pressure from the steam pipe is also supplied in this case by pipe connection 45.

During periods of small pressure difference between the saturated and superheated sides of the superheater,in other words,'during periods when the locomotive is moving slowly with the throttle open, pipe 43 willbe supplying no steam to the upper side of piston 59; valve 55 will consequently be in its upper position, due to the pressure of spring 61; pistons 50 and 51 will be depressed, and valves 17 and 18 with them; and the steam flow will be through the two sections of the superhea'ter in series. The opposite state of aifairs,piston 59 and valve 55 in their lower position,and pistons 50 and 51, and valves 17 and 18 in their upper, with a consequent flow through the two superheater sections in parallel, will occur when the pressure diflere'nce between the saturated and superheated sides of the superheater reaches-the predetermined amount. I 1

The two valves 17 and 18 act in unison and their functions may be performed by a single combination valve. This is illus trated in Figs. 6 and 7.

One portion of the valve 62 controls ports 63 and 64, while another portion controls ports 65 and 66. The position of the composite valve is altered by means of piston 67, connected to it by rod 68. Piston 67 assumes its two positions in response to the amount of the superheater, exactly as in the two cases first described. T

With the valve 62 in the position indicated in the drawing, steam from the saturated side of the superheater flows simultaneously to all the chambers 13, and is delivered by the superheater elements (not shown) simultaneously to all chambers 14.

If the valve 62 is shifted to its other position, the saturated steam passes first through ports 64 to those chambers 14 to the right of (below, as seen in Fig. 7) partition 16, thence by the connected superheater elements to chambers A-A, thence to chambers BB by way of cross-channel. 15, and .then by the attached super-heater elements to the remaining chambers 14; whence they reach the two outlets 12--l2, the one directly connecting channel 27.

Figs. 8 to 10 illustrate a form of my de" vice in which the position of the valve 62, which is in construction identical with the similarly'numbered valve of Fig. 6, is controlled automatically directly in response to the amount of steam flow from the dry.

pips. 10.

xtending forward from the valve is the stem 68, connected to piston 67, the latter reciprocable in the cylinder 79. Connected to the two ends of the latter are the pipes 80 and 81, to which steam is supplied by pipe 82, the supply being controlled by valve 83. This valve is shown in an enlarged section in Fig. 9. With the valve in the position indicated in this enlarged view, steam would flow through pipe 81, while any pressure in 80 would be relieved through the exhaust pipe 84. In the opposite position, the valve would allow steam to reach the other end of cylinder 7 9 through pipe 80, and at the same time relieve pressure in pipe 81 by exhaust 84.

Valve 83 has its position determined by the position of the flap valve 85 in the connection 86, which carries the steam from the dry pipe 10 to the" header proper. This valve is pivoted on the shaft 87, which extends through the connection 86. Keyed to 87 are the arm 88 and sector 89. The former is connected with piston rod 90 by means of the short link 91. The piston 90 reciprocates in casing 92, its motion toward the left being yieldingly opposed by spring 93. With sector 89 there meshes the pinion 94, which in turn connects with the valve 83.

Whenv there is little steam flowing the valve 85 will open a small distance only, and valve 83 will be in approximately the posi' tion of Fig. 9. Steam will in that case be supplied through pipe 81 to the farther end of casing 7 9, with the result that the piston 67 and valve 62 assume the position shown in Fig. 8. When the steam flow increases to a certain predetermined point, valve 83 will deliver steam to pipe 80, with the result that valve 62 assumes its other position. The eifect of the two positions of valve 62 have been sufficiently pointed out in connection with the other forms of my device.

What I claim is 1. In a locomotive, the combination of a superheater comprising a plurality of elements, and means automatically to direct the flow of steam in response to the rate of the flow either directly to all of the elements or first to a number of the elements less than the whole and thereafter to the remaining ones.

2. In a locomotive, the combination of a superheater comprising a plurality of elements, and means automatically to direct the flow of steam so that at rates of flow below a predetermined one the steam passes first through a number of elements less than the whole and thereafter through the remaining ones, and at rates of fiow above the predetermined one the steam is delivered directly to all of the elements.

,3.ln apparatus of the class described, the

combination of a header having two chambers, one of which is farther subdivided into two parts; means to deliver live steam to the first of the two chambers and means to discharge steam from each of the subdivisions of the other chamber; and means to divert the steam from the first chamber to one of the subdivisions of the second, and simultaneously to interrupt the means discharging steam from this subdivision.

4. In a boiler the combination of a plurality of tubular two-ended superheater elements; a header having two chambers, to each of which one end of each element is secured; a partition in one of said chambers dividing it into two subdivisions; a transverse channel with which one of said subdivisions is in communication; a steam inlet; a duct connecting the steam inlet with the other of the subdivisions; a steam outlet from the transversechannel; and means simultaneously to establish communication between the second subdivisions and the transverse channel, to interrupt the communication by way of the duct from the steam inlet to the second subdivision and to establish communication between the steam inlet and the first chamber.

5. In a boiler, the combination ofa plurality of flues; tubular, two-ended superheater elements located in the fines; a header having two chambers to each of which one end 0 each element is secured; a'partition in one of the chambers dividing it into two subdivisions; a channel to which steam is supplied from the boiler and which communicates with one of the chambers and with the first of the subdivisions of the other; a steam outlet in communication with both subdivisions of the second chamber; and means to cut oil the communication from the steam supply to the first chamber and that from the first subdivision to the outlet, or to cut oil the communication from the steam supply to the first subdivision.

6. In a boiler, the combination of a plurality of lines tubular, two-ended superheater elements located in the lines; a header having two chambers to each of which one end of each element is secured; a partition in one of the chambers dividing it into two subdivisions; a channel to which steam is supplied from the boiler and which communicates with one of the chambers and with the first of the subdivisions of the other; a steam outlet in communication with both subdivisions of the second chamber and means acting responsively to the rate of steam consumption to cut off the communication from the steam supply to the first chamber and that from the first subdivision to the outlet, or to cut oil the communication from the steam a boiler, the combination of a plurality of flues; tubular, two-ended superheater elements located in the flues; a header havin two chambers to each of which one end 0 each element is secured; a partition in one of the chambers dividing it into two subdivisions; a channel to which steam is supplied from the boiler and which communicates with one of the chambers and with the first of the subdivisions of the other; a steam outlet in communication with both subdivisions of the second chamber; and automatic means to cut off the communication from the steam supply to the first chamber and that from the first subdivision to the outlet at times when the steam consumption is below a certain rate, and to cut off the communication from the steam supply to the first subdivision when the steam consumption isabove that rate.

8. In a boiler, the combination of a plurality of flues; tubular, two-ended superheater elements located in the flues; a header municates with one of the chambers and Y with the first of the subdivisions of the other; a steam outlet in communication with both subdivisions of the second chamber; and valve mechanism operative. automatically in response to the pressure difi'erence between the steam supply and the steam outlet to cut oil the communication from the steam supply to the first chamber and that from the first subdivision to the outlet when the pressure difference is below a predetermined amount, and to cut off the communication from the steam supply to the first subdivision when the difi'erence is above the predetermined amount.

NEAL TRIMBLE McKEE. 

